1. Technical Field
The present invention relates to a fluid ejection device and a medical device including the fluid ejection device.
2. Related Art
In a fluid ejection device such as a water jet knife that excises or incises living tissue using high-pressure fluid, a pump that supplies fluid (for example, physiological saline or Ringer's solution) at stable pressure over a long period of time is required. For example, JP-T-2010-509542 discloses a medical pump employing a technique of supplying fluid without interruption by alternately operating a plurality of pistons (plungers).
However, the above technique of the related art has a problem in that the mechanism for driving the plurality of plungers and the control means thereof are complex. Moreover, there is another problem in that it is difficult to secure high reliability of the pump, simplify the maintenance, and decrease manufacturing costs. On the other hand, a single plunger may be used in order to simplify the structure or the control thereof. However, if a single plunger is used, the size of the pump increases since a large amount of fluid has to be secured in a fluid supply unit, and an amount of fluid sufficient for ejection has to be secured in a pump chamber.